A gas turbine includes a rotor which rotates about an axis and a casing which covers the rotor. The rotor includes a rotor shaft and a plurality of blades attached to the rotor shaft. A plurality of vanes are provided inside the casing.
Each of the blades includes a blade body which extends in a radial direction with respect to an axis, a platform provided inside the blade body in the radial direction, and a blade root provided inside the platform in the radial direction. The blade body of the blade is disposed in a combustion gas flow passage through which a combustion gas passes. The platform defines a position of the combustion gas flow passage on the inside in the radial direction. The blade root is fixed to the rotor shaft.
Airfoil bodies of the gas turbine such as the vanes and the blades are exposed to a high-temperature combustion gas. Accordingly, the blades of the gas turbine are cooled by causing a cooling medium to flow into the blades. For example, in each of blades described in Japanese Unexamined Patent Application, First Publication No. 2013-124665, a cooling channel through which a cooling medium flows is formed in a tip cap forming a top plate. In the tip cap, a tip rib as a thinning is provided on a radially outer end portion of a blade body substrate.